Timing Issue

[spayne83]

I decided to check the timing on my bike before I changed the jets out and I am stumped. I followed the instructions in the manual exactly, had a steady 950-1050 rpm idle with the engine fully warmed up, clamp on spark wire #1, but when I went to check the timing I would see the marks almost line up and then spin around and reverse and continue swinging back and forth. The timing marks never stood still. I have done timing on cars and never seen this happen before. It is my understanding that the timing marks would only move if the engine were revved, but I never moved the throttle and the tach on the timing gun didn't move more than 100 rpm ever.

Am I doing it wrong, or am I just going crazy?

[motoman]

I decided to check the timing on my bike before I changed the jets out and I am stumped. I followed the instructions in the manual exactly, had a steady 950-1050 rpm idle with the engine fully warmed up, clamp on spark wire #1, but when I went to check the timing I would see the marks almost line up and then spin around and reverse and continue swinging back and forth. The timing marks never stood still. I have done timing on cars and never seen this happen before. It is my understanding that the timing marks would only move if the engine were revved, but I never moved the throttle and the tach on the timing gun didn't move more than 100 rpm ever.

Am I doing it wrong, or am I just going crazy?

Never had a hankerin' or need to check timing on mine. I can tell you that in the automotive world, a timing mark that moves around under the firing lite is a definite indication of a loose timing chain or worn distributor bushing. The second one doesen't apply here.. If you haven't correctly made the timing chain adjustment, could be your issue. If you haven't swapped out that walt disney designed mickey mouse POS stock tensioner for an auto adjuster, I would advise to do so.....ASAP.

[BA80]

The timing chain couldn't be the issue on an XS since the distributor, so to speak, runs directly off the crankshaft. The cams haven't got a thing to do with ignition timing.

That doesn't make any sense spayne. The only thing I can think of that could possibly cause that is a problem with the centrifugal advance unit undr the breaker plate. Or, possibly it has the wrong TCI on it. Does the number on your TCI begin with 2H7?

[spayne83]

Based off the pictures here: http://www.xs11.com/forum/showthread...t+spark&page=3

And my picture:



There is no lettering in the actual plastic like on the 2H7 and I remember the paths on the board were light green, not gold.

I think that I have the wrong TCI on my bike. Damn it! Here I am chasing my tail because of the PO!!! Looks like I need to get the right TCI and then I can set the timing.

[BA80]

Sounds like you may have a TCI for an 81 on there.

[spayne83]

I just ordered a TCI (http://www.ebay.com/itm/1980-1979-19...p2047675.l2557), so we will see if this solves some of the problems. One step forward, two steps back...

[DGXSER]

The 2H7 TCI does not have a tag of color on it. The 4RO from the 81 model has a yellow tag on it, and the 4RO designation. The 10M from the XJ has a green tag on it as well as the 10M designation.

So look carefully at your TCI and see what part no is engraved in it.

[motoman]

The timing chain couldn't be the issue on an XS since the distributor, so to speak, runs directly off the crankshaft. The cams haven't got a thing to do with ignition timing.

That doesn't make any sense spayne. The only thing I can think of that could possibly cause that is a problem with the centrifugal advance unit undr the breaker plate. Or, possibly it has the wrong TCI on it. Does the number on your TCI begin with 2H7?

Readin' your response, and re-thinkin' it, I stand corrected Greg. Centrifical advance is only physical piece that could waver that. Electronically, think U nailed it with faulty or incorrect TCI.

[SFerinTEXAS]

Vacuum advance hooked to intake , not the carb will make it erratic.

[motoman]

Vacuum advance hooked to intake , not the carb will make it erratic.

That it will, but should be disconnected and barb on carb capped to look at timeing anyways.

[spayne83]

It looks like the wrong TCI. Am I correct?

[oldnortonrider]

Yep; it's the wrong one; that board is definitely "4R0", to be used with the 1981 that is WITHOUT the centrifugal advance. The 4R0 designation on your TCI has been lost, that is on a sticker that ain't on your box anymore. The "2H7"s have raised letters that's permanent on the face of the cover. PO interchanged the wrong TCI. The 2H7's are plentiful; easy to find...................

[oldnortonrider]

Go here ~~> http://www.xs11.com/forum/showthread...7+board&page=3 ~~ post no.32 for pics of the TCI different boards; excellent thread re TCI's...................

[TopCatGr58]

Hey Folks,

I'm a little late to this party, but I think we're jumping to conclusions!

Looking at his photo...that's definitely not a stock seat pan and wiring setup! SO...even though his bike says it's a 79 SF, I don't recall any info regarding his engine and ignition components. Folks have swapped both engines as well as just ignition components to get bikes running.

SO...I would ask Spayne to first check his engine serial number. Next, check his ignition components on the crank to be sure he has the 2H7 parts...both centrifugal and vac. adv. parts. THEN if he does have the proper 2H7 engine and timing components, then we can be sure that he doesn't NEED the 4RO TCI unit. But if the PO put on the 4RO timing parts on the crank, then he actually would have and need the 4RO TCI.

Now, I've got an 81 with the 4RO system, but I've never checked my timing because my timing plate slots are SOLID, filled in, I can't make any adjustments to it if I wanted to, so there wasn't any real need for me to check it with a light. It works, has worked, and hopefully will keep working.

Just trying to be thorough...I don't want to assume too much!

T.C.

[DGXSER]

Agreed TC, just because it is the 4RO TCI, does not make it wrong. If the timing set up was also swapped, it should run just fine.